As the types of presentations in a conference become more and more diversified, the projector becomes necessary equipment in almost any conference. Thus, consumers are demanding more about the performance of the projector. Since the LCD projector became available in the market, manufacturers have endeavored to improve the brightness level of the projector, so as to make possible a perfect presentation even in a bright indoor environment. In order to project a clear image in a bright indoor environment without having to turn off the lighting or draw the curtains in the room, the performance of the lamp of the projector needs to be improved. Therefore, the wattage of the lamp used in the projector becomes higher and higher. In this condition, it is necessary to provide a light source module with ideal cooling performance, because if the cooling process is not good enough, the devices inside the projector may be terribly damaged.
As is known to all, during operation the cooling method of the projector is provided in order to keep the temperature inside the projector in a safety range.
After the projector operates for a period of time, the inside of the projector and the light source module is still at an undesired high temperature. Thus, the cooling method during turning off the projector is conventionally configured to cool the projector for a predetermined period of time by a cooling device, such as a fan. The projector is truly turned off after the predetermined period of cooling to make sure the temperature is lowered to a safety range. The predetermined period of cooling is usually decided according to experiments.
The common cooling method of the projector and its disadvantages are discussed in the following divided in three phases, the turning on phase, the operating phase, and the turning off phase.
Generally, if the projector is operated in a correct manner, the cooling device is able to cool down the projector during turning off the projector. However, it always keeps users waiting for a period of time before completely turning off the power. Users waste a lot of time on waiting. Besides, the fan inside the projector is usually set in full-speed rotation in order to shorten the cooling period, and full-speed rotation makes unpleasant noise. Moreover, the ambient temperature can affect the efficiency of the cooling method in lowering the temperature. For example, a higher ambient temperature, i.e. a bad condition for cooling, may result in insufficient cooling, and even cause a damage to the lamp or other devices inside the projector. On the other hand, a lower ambient temperature, i.e. a good condition for cooling, may result in waste of users' time on waiting for the cooling method to complete its job.
Furthermore, if the projector abnormally shuts down, due to such as power failure or wrong operation by users, a large amount of residual heat will remain inside the projector. Thus, when the projector is immediately rebooted, the conventional design is to first perform the cooling for a period of time to remove the residual heat before the users can operate the projector. However, if the time interval between the abnormal shut down and rebooting is long enough for completely cooling the projector, the predetermined cooling period is in fact not necessary and causes a waste of time. Moreover, the abnormal shut down can make the projector unable to remove the heat inside if the projector has operated for a long time. Even the predetermined cooling time period may not be long enough and so the projector may not be rebooted successfully or function properly.
As described above, the conventional cooling control method is unable to cope with various conditions during operation, and results not only in inconvenience of operation but also damage of the projector. Therefore, it is required to provide a cooling control method and apparatus for flexibly adjusting the cooling time period according to various operation conditions.